SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d9c1dc20deee26de17247c0e4358c3aaf5c39608cb79475f066b3274ad1c21e' 
  AND token = '+Yko/2SWZim6nHapBzOcQlSSKuGzCrV7JvMidRw2AxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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