SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e3bf58ea92c847c6810fe38b4906a6447e9c9292cf5d535e9563a9f1a3c697' 
  AND token = 'K+XVqvSroJkDGIKkH3fNSPYisW3QmhCpHPKAKT417DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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