SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90252f76543d0773ca40104833bc130bfc29a6c68c10f745a091c7c411de124a' 
  AND token = 'sgnFA5BzZL0aMqhFJPWBqzyMPLjo4gxIcpB8Pcn8RWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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