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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de3d46068cdddb2ed32a8b2fdcbf907271b8a3cd1ea0019c7c4be4ad9f68f7d1' 
  AND token = 'Rzbh+/KRncupPV27dctDkTPVrFFhoZi6GjGBA+e0PL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}