SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc253212ddadb3fc38476ab9ad5581aacdab43807d5be842cf87883302e80c92' 
  AND token = 'n8ZrYWqX5mV66wTdnX2jlt10/qTCHoNrggkjMYnv3Gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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