SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73b121272a5df8beea87d3e4fe176593906b5749d045925441c06e2221d8195' 
  AND token = 'g/5+yNhnCxa3bRmrTPEMquJzvDwmpx9IJpHIFxlUyqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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