SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b475b40737791874a29879939ce224729ae25592ba0b2a77ba4555041db9cfde' 
  AND token = 'EJbL3dwgLOGlMDdHTPGN14ZJ3+/ruUq9AJBpkZMg/4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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