SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5bfc0ed16c47c61808ea281eb24f70599defad3c77b27230eda05b2d8218723' 
  AND token = 'Zng4udziPteTlqOwZaYkzPyuMJe7vseR0Fb/y0jhw8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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