SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f3319c249f004808e02c30690358ad412671e19f87b1edddfff4145dca34cc' 
  AND token = 'hmIEtXXuCj9bHa9gcA32zf0jNLdb2aBzX15Iaac4KiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}