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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9a2fb77174cfbd07e2398df67a7252a5eeefaadfabe7808c1a0897e60418393' 
  AND token = '982mbi2XMcv+Py9ZUgz26CS5SS6IErfERcivj8BTgQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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