SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27a45e1bc2faa886febc4859dca2eeeab6a99c33736e6e5758d3209a199494d' 
  AND token = '2ur2w+393gcYQgg1tG3TWYSYxmRoeqWz5pAqbC16ztI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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