SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74551f73adc2fc401e7384b32cee2b14fa66b22ce6ba65ff488c3324174be4d2' 
  AND token = 'UKrV6E6Ahrwe+33kucCp5JNQfYhU8vpARMB0dEzTOS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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