SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e775a100ef9f0c6d82f94251c4757998137af8fa0123508c36a14d9a14f29b7' 
  AND token = '3Bdaeav14bqEfR8jfVSySoIEtwifMvclWCUvDDI/z1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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