SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '666dd16bbfc21fa1e02d7157d4047ddf40401e4d02251f828943b90d8cddd454' 
  AND token = 'UDOlKdtWlxh0VIn4mH17sUdgG0wQ2iitzsgT4QdlClE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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