SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e826133174cfd9bc4cd43a041acd7104cfe77782e9e055e285a1b59aee4ad21b' 
  AND token = 'GqEym3tL59fhLYumEwxI2I46M9JqwQVMyelrqN8wwCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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