SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '700baac39141870f9f02c8df367bf6e8384783b4194dc4a500f0407c272614bc' 
  AND token = 'UOOUQdHfMtHyboUg69npuFpvvEJIas8GtzBmAJbqqco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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