SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45a7bdf8346f8f73c9a14f961e272a655d74160c7045e880901d9138618d0284' 
  AND token = 'yRcqsnT2ATHXnYTiRqSvHMuHA8c1r+9E1qXHK7puums=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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