SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfcb17ee9b7b7aa4da15752849a00dc2f64000ac8966556089f22e67ede5e1df' 
  AND token = '3SaFwNnMEllETj5ihkBWJzh1/nbu0ld7mWg9QFhT+JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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