SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbca4ac4d828a6cd76cd82666d0763b67f690fa2be3569989c1993a7963ac3e0' 
  AND token = '/E0PAJVFIRzWzKxl9wGcwe7SjI+Y5HouOrym3YVYpLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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