SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e881ced83883332acfa12b70660599d2848e2581ab2e8818a3338f052b6a84' 
  AND token = 'EBQrEdXgvbMsVwAfjirIFTwVM/HUuJjbh+xfXHP9iDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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