SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce0cf46689a905a32286dc380d31b14ae3eaaad0b6e45f902513108eb4ebd99c' 
  AND token = 'JCP1nMDSAdyeakcBlqgowaWofdNVNr3pu51Z5objOs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}