SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46309563d48373be6731daa90f20f7ba477cb1ab182e332ec43d289aa1d05331' 
  AND token = 'likA6gdaHZdiKKe9r3B1vfTU5nQ70ApziEPN2/UoCgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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