SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51bcf69989efcd554d9491a3b35a2938ddae231d70dcc888b1628434f29cfaeb' 
  AND token = '+w90zLSsojWP89TxDmHolBejK9m1H+gUCPCEiDjzjak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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