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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d9b9ec7170f62bc7a15b9f818913d287a42ea7c8573b267d914a5de09736a9f' 
  AND token = 'nZfOtqpnOigtI3zaoOmrF78fzXnnzYNjC2vC3utliuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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