SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8f997601634c50a5a91476f0a44270ec8f7a1382967ba24767d588f9b2560b5' 
  AND token = 'sIIX7cUaKsKNbKzXwzOsrfqrTOObFzeBjQciONw30c8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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