SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f835628fbabb3553cd7721ff27c99f28f99df89714835035d4d303291b0764a' 
  AND token = '2Q9oJaF2wJZcE71hvdWdf1WAnZwtNKxkFLYZ9mUXjvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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