SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf509d4b956723230b0a9029137798423e8e855debcdc422c337430b163c16e3' 
  AND token = 'uan5O/E+LGXUPYiPNHCdtLPeaYOWF05YiL3Ni178B4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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