SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '51d817a6483f791fa462859329b3b0013ab39e11478c474f0132c367c2c7bfd3' 
  AND token = 'tKbFhStzmH3l0/F/1HzxNpAJfmNh0MMK+3kRwbZ/Pfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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