SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd70d6860aa932bb66b00b8cbbe873d8eb04aa5edab05e1ecb23f049dc2a967ac' 
  AND token = '+NDDL4259aYjrfuZym5WKoVDbt8cA2agjEqhvL98bP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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