SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644b6b015993dcb791d4b4277d50307f59ffaae6e39c6e0f82f4ed2b5a22277c' 
  AND token = 'xKCeXvTd1G/aZRQkXAyJ7TvurGEkLD//aAbZvYFtpQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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