SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d1e21f79d236db112d2406a457cddb1be1f5cc726dbe87cef58ab2604e426b8' 
  AND token = 'k3CMsfkW1C7+taA28s8+W1qjYoZAk3EWTAKVlP0hN68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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