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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '564f6761d3d3c2609ed03fdfb06ba74fb8c19ee0643a631b5b865a6ea548acc4' 
  AND token = 'H3/lDvqoiTP8ZGiwbRdr8wK4F2/ugOY9nOpigxNGykM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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