SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '238e409a058770d4d7a83d1bd0dc8f80a9556b3401e8cedb6fa3b27350390996' 
  AND token = 'vOKRuGSTMvKrH83uIzX2VmgBatwIJccbXjmmb5arZbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}