SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5237b6ba7490e29940f6065168abfbf0f69605d2064d757340b715e6587ec40' 
  AND token = '/hZ8yK5a0UxLxFlSqbLALFAQQsBlimRnYeXRgn4cmlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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