SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fd8bd8e29dc6ab5c008b5c594830a98e2eeea320b8ff2e83a03dd9656d41ee2f' 
  AND token = 'q8PTfCu+cqBiJt/6ZknCtO2sfofAxqkXzDsxdw9WWec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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