SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6d89d3a5dbfca01c0225add305e7305f9be2cb9f8c75ea68b6de1fea5b0c1c0' 
  AND token = 'Hh7jSL/Z+Li0Q6BsDs9YGKhdAIiqglmKVkfJ2s5RSPo=' 
  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"
    }
  }
}