SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ea8406b93ee91be5b9b05aaffba0528f0207a12a8888d68fe997c777ca29bb8' 
  AND token = 'D6rTF1QtIxoX4kXqA9L3bQs24zhKxO6MfasVJWQZ49Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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