SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa3f0537720f70e4773b1730dbb572c3db0a09972eef0957972a27c9171816b9' 
  AND token = 'mYMtV2i48M5ZUOlw84LLYLkI+gGy4Ya1by/si9jb8is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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