SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06c42a9340c18390f99018002f368d2f69ae47142bf3b1953aadb4e4559d5ff7' 
  AND token = 'yjZw/pZpVIYmjlzAtperTlH+A1ThCo1JU/qrqZ8rgyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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