SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37afcd07e35fa9f7a2332b090df256617a1f15b4191423cc7455197a5850334d' 
  AND token = '35PBX1SWBWTUnHMKwR0J1VByHBLPTfqgaZ5pk0IMSQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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