SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6925de3976bbdd4707fcfb357eb78c6104150cb724bd21de8c798b506d3305c5' 
  AND token = 'ON+gQdAIOh+fdLhziI53mz/8LBvY6CtN8qquRg17Euw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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