SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1c11cf3959f15a07d1ed50f4a4c7b615a5bf0e46d2c039d8c902e9c9c220aad' 
  AND token = 'DT7xiIIjdjHGBMMdKfBTnhGy7UymaJvmDkCEeyqaxRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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