SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc028db0e7f903d49d914ded6ba800403566d97d6c6c7219d65b0c10768714e2' 
  AND token = 'gb5sMVhQJfj4qE3qliHvdfe27G1kCbAmB0XMwQ8BRtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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