SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e155139b965cade5d229a2aaae5dc25250727cada077e0fcde349451e036c8c' 
  AND token = 'KmLGS9woYRQWVzOQi4kta/iI2efzjZxp+INtmMxRhz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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