SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85794b3e1f1d5c550081f8846382f4c8591511bb1620e185f7a22921b5aa1a4e' 
  AND token = 'NlZvj3rHSTOCXkLRuFQLJUzmW4KmhfFr/Z+CdnDFPW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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