SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acb8ca24d94f31594cebe9ea7abffe165bcb1940420fad44501ca05738655b7c' 
  AND token = 'aerbfojWi4jJd3NAy7/D3ZhRYfuQ+lnTqyaZpM00DhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}