SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9b6a2242259fffc38f75f82324c2418a301c099fa41034c16d0bc603166f968' 
  AND token = 'wzL6D0VUdwDeyQiIuOGV50JD2gIRKQtSmS/KV8nA+fA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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