SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fe208b1bbdd71eab65c6aa836ee73beafa9cd787fe768c417d32958cbd5cbe0' 
  AND token = 'VKetSnmUIbsSvLOsacGj3HmtLObyhzL7GELdqkWg3t8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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