SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0cb41f6f8f9074c219efceeed405a27274bfc320f1539bda0ea8e5d0dd65552' 
  AND token = 'UpkL99ujApRQABJhPB/znao281TkEZG6Rtca15Fddbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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