SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ded813b0fcba9ad89465e66646326d47f77806f03b7e983e011caa5a83e3b552' 
  AND token = 'td0IgH3jHC+/FTuwUjcUOCJwwa+Q6jgiFDZXF+RTmCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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