SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d787c4fb4f0777de1982a0bba03b2837e19b506175c34de0f3af06853e75c7' 
  AND token = 'oPKJj7v0M5kpDKatxzAZWzEi9Sqgrjvf/Yufl6t/N+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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