SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18b0bca14b847a14ed7528b63880a7bb9dbd7d11789f9d14dbbb2854cada619b' 
  AND token = 'kc62jLJOvxyPuHTy8zVJPZs7oWhN42OBrKM4JoCwiXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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