SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde2f3654d6253487ec226c6dd1049c6e5da04097957c4affe597d22355203b1' 
  AND token = '9S9B7h1/2S4ASYRmqIJMSJmS9JP2NwIUnklNvx+pY5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}