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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21d3a67e0cfe06091c264a181d52062fae5a52956a4e5318ee8ce38ef743c024' 
  AND token = 'gzf8t3VerERrFAZdmaauPpRcvLp7uVpybunvEoHoLaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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