SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e3d04a7d06214d6964d25629f87748aaad85e9c6fb774093df354354b8fb42' 
  AND token = 'KgiintsPNl18uw/RWwFqXzP53qZSM1QibPVs96SxNRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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