SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5e2469bcecfc2d66de94433c59078143c9d7f01652384af647a87f342fe3573' 
  AND token = 'GuhmepWFc0OlSDoNAXZeWmQ2+6D8H2MUGBy/eLrWoHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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