SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cab644f039c16613df95198bfccaae332cca73f5f77ba1db50690d28bf91629' 
  AND token = '0s3AzAZSwshJdGgMevbO4Gd/OVjBfopCjKIcvpFwaHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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