SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d7f90acecaabba66582eda1c3e53aebecafae0eb73d125efa9e3f123d4c54c4' 
  AND token = '/8PEEIw4yFKpLfEOBWPR18BG2AESq3qDzODGDELTz98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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