SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf40162b99810b2b39502c37c33f58e4641ccda964dfe2c23f02babd2df65585' 
  AND token = 'Rr8UfrzkP6NsqdUXo+Gh9zgwcd6UX46NfEjSx1Hpu1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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