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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '355762e5d3e619f03602dbd86ee0c2531d1e374f367d9f8d698045b4817e66f0' 
  AND token = '19hS/7E9gynsBuaMTG5ogBjwDjDLHCX8NgmSTrtw1u4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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