SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a484565e8342e84b0e9f168f0f290a9adc974b37b15f2bb00460919e8c1740a' 
  AND token = '7CWJb6KVpJz/7jpFbushgY4ChoTfyoG07tZAS6HBhJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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