SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a688130863b3d085cab5d6ef34c6621d73a198a48a9133434b5f33670ffcd81' 
  AND token = 'fP4CRHpnVZbHiU3AwjO50PXzUeEvgdLyrWX3wIeis9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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