SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5812faa627daf6e884f3adcbeca88edc870c8cf6d33f4280ea381456353f9f62' 
  AND token = 'PO9VxZUbT/NiJeKcMNFIpr51UUILAbzNhY9BNPoHcRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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