SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ba6175d18ebf20195509c9d4c12969810e7663e2819be7ac279c3a1c8fae15b' 
  AND token = '6IHkEXYtlkVeE6Y/MGwxJm6RgQ1CvXHYKa7Wtvn+dok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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