SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3aa7d259d7dba2fa26d3eb8906a083cf1359810d8b50c353eded093e8c8087d' 
  AND token = 'W8sdOlfoR07TPIx2SvXwnr/GfaDNPeYwW6ZcflUYMlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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