SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b530710406e12944af3410f81cf2d7e604f595b2646b5f9a9d1ff1878a8b70db' 
  AND token = 'gc+oNUnKVCNvgLHWg+4UguTlEzKFaXdysXOxEr/X4oY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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