SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8219556b9130a06d8991f8dc14a1cf528b820b809599178133b4f0560f26857d' 
  AND token = 'uER8WoFQV9KZQvZpVL0EiAQu3rq52DXFrdyqnq/nYT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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