SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a55544498b3bd4bf7076f70ef67b26ef8af9ea0537ab1722a0c5de0897c23a5c' 
  AND token = 'JnuzJe1o7w0gHd4ztjQBP1/ErMNKivUoe9Z6zgx1d3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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