SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcee2ff2a87c8382357019d3350bbfe15e537fb77adf60a91e1b7abdcbf521dc' 
  AND token = '/HfILHjjzYFmJiYC/KldgU/wC+t2z/hZW9oG1GaHhI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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