SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14e28314efb2923132ffa0311a6ee53928585f4431c398531b876eadeb12c571' 
  AND token = 'mThPx2rWwsgtICSt3JLh9UOogOPCiSt/Fo2FgLHVsQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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