SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3dd7f02033a61495cd560f0c86b19ed3d714993d1f8b543b6936ba2570941f5' 
  AND token = 'Yr8pwVWB+rPDp/p1z3iQkyz+gSSYfffxFILblsoq5qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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