SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0f3bff85a91eea5da578d29dbf8189974381f6e547861f7ac5b02d961e1c39b' 
  AND token = 'ihyWYwB61p5oBDMfG9ajql0gSsznRxKfsrPOshO9YjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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