SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48a23c121bdf32cfd90c0146181286337d28cfda5bb78a2428b0edfb8c067128' 
  AND token = 'cjMVfehyGbE5TYNBVoSuq3hze4d219uS+jcY8ibWzmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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