SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5774d63a001a1fece03bd90322151f20234f65a8dfeb656e412084b91ba5c4a7' 
  AND token = 'm3S0Ca+7OydM4j1MWMj6u3P51wUNgUWJvO2GftUU1vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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