SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ed2e37e3656a73c6809b654ea6b93daa203a3ce45b5679268287dcf869f00e' 
  AND token = 'Ei2yhPniu8Y2ZhtEniww0taNFTZuVCkCqd5khBAAgD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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