SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b05259cb7a8085dbbe0dd24f14cd9ac6cf0921e48de3bdf99105bf3e857f0469' 
  AND token = 'HydblIFf5QxOsH+2zSWEpEHh0fngRlPHG7eVfddMY1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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