SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44550b5e2610c2603cd0e8d44446381284efeaff1eb9167f32600596e0d3e466' 
  AND token = '8iaEtMfWsD/RdMMzMMLHbviNqGOG+cQXlkZslOwL9Mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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