SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66f87a75ade3707ec2636ee6dd693b20ee0ccf2ab3866e53580d6dc4c1da83c2' 
  AND token = 'RgaFFaWJsEPKm9JBexlur5UiupRMw5Ug26ikEU0TH+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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