SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9bc430429cb45feb9773734c61b3d31a0e460a2b423cd5ffeac61d2df266a98' 
  AND token = 'lz+bUaTkvaVfKgxek5TE0jbsRTnmSJAOWU3mFBdKyX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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