SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9dc5afcec3140540de7f81d745be9d3345972c70c9e73b73acaacccd8c8a9fd' 
  AND token = 'yWScBIPu/I03CduUjYrb5FteXxUgPcdnAE+GwwB1RNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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