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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd52200c26f648186b65a8ee051723cc01cdff021a0927756e5aab4164d0c37da' 
  AND token = 'ViqbQQn9j05ZoZAOjRdHp5NoNzTwmeAfVteC/8Q21+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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