SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0536ad5ca61e01159972b59b33499de4e0e7457193d447756ffd52438b52fc1c' 
  AND token = 'MGmrfmX2Fjxv2llFQ+K1bqC5eYOMjVmN2BCWcorEeDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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