SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4ab48c2457eac82672031fa62d9d2ef18f21cb64e5aa22a82c7b098cd512c23' 
  AND token = 'BcMs8/sYw9ucvHMcCPxYzZkplmNWfVDa4wNP/0pxE4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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