SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72ec501c31f966fb3892bda65c61af57f794521fbc845f13f420fdb87f0fcd62' 
  AND token = 'vkB9yZmtC2AminzumgnkHUSSOYyMdd9nic0cpT09Cb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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