SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '984aa59b53ad19d0edbfb7874125c7e947c474677b99db172e0c225839ff2149' 
  AND token = '+8ahWpuI4lzVGGHTFrzjldbktWCI6EzCiNvadQPS9EM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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