SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7101fe287521c3eef47a262a6b43512d0614d9af50f6e0d7fb1207c7e2642229' 
  AND token = 'lTNgvdLR2O6phVYYrD8cy1w366NIOMTXEavUpMbkOHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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