SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14c97a6a80559b520de647ca6fc8cefbe40bc5138251bf7b41bab22abc7220e4' 
  AND token = 'HyDcqcO3rBZbcSlsmlLi5BCuJGohmG54VI2BPMqsR2Q=' 
  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"
    }
  }
}