SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '947ec225e5fbff5757885b69de4d0fb7c3cff598f888599a747b096b07ce64a0' 
  AND token = 'OikTaqHxlInmqp1UKkgoeEL0oMPvOw9lm5i3TGd92XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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