SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b3d8fd2bee9b0b793b4dd27368ad896157ceae73ac077e65f9758c69cfe045f5' 
  AND token = '5842tpqVCGnrQPu6V6vtLTsW9bWWV6lB4MNQ/vVwIwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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