SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a7573aa389cf3cf2307c926987540b6f78ac8ce3677a12673db8fe2b4a58901' 
  AND token = 'fH/fDmRtR8qqlHSXB9JyUKVLvNQm/qtoSW2tF+KQyJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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