SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c042e74c01074a95df5a5609e6a43a71c1847709490de527e34e75c5ce289a1' 
  AND token = 'JfN2sHLR/ZmNhkuF92Y2JProhCBACEKC2m+u9HWtECs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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