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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6ba50e59e241aeb7f8e9ca0d35c33aa0514113ea6cf2a85604201abbb89b237' 
  AND token = 'D+E8IHB6dNs/sglp5x5zzdpKgoFm6/ZRYW1w7Q2T9kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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