SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cb09145c27002f2ae193429adc8fa7fd5f21304f27f5cb24a1888c0db3825fa' 
  AND token = 'f6obqYiVsB+tVO3rmevZAWJ1CmfqtLWZplp0OnXFnUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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