SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0054eacef7c8aff1a86fc57ef47d63eff6842578868293bf964620a67ad82d8' 
  AND token = 'dqFE5jmOERok9rz3B8OSOLtuv8bkXxCrAD3r4pIEoPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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