SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c32e8dd1eb37f2bf544fc1fc9683a03e5a681005bd851be08c8910c186ce1ee' 
  AND token = 'szk1zor5yd+awgslLNARzFpi+oqcDrYdiPGAqFuOS6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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