SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a116e59ee5044ded607528a192a28abfe019ffe4006dff3f7519e814f84ed5bc' 
  AND token = 'svxDyIuf8GVvDcWn5rDy3bq+uvMFFNYIAnXTX9K9UqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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