SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd121432449dcd28448867935be23ac6a41d9f5176a3ff045fdd57545ddc06566' 
  AND token = 'kJaAs4ratgncGP4gWY9KiGpeqNapGMCPP+GdyyjQuYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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