SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '155254bd878f034ffa1d20d578f4f36389747537e47b086a742e1da4b4d46e8a' 
  AND token = 'C9VxQ/jZyfK+9/kl4yxKuDOVfytyUgcxyfKbOyijJrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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