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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd3c2b134280e13c5353b0e83986e32f8f1d0f0a399f8083d2f1eea5cf0fd84' 
  AND token = 'KdztCZhNQfR86dbcfVhftv3uTZCh5SOsYjELqpK+794=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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