SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387c5e04c58c81da03f2351b2bfd02ee0fa9f8017a1a2e83181295f1ce972c75' 
  AND token = 'hVenxBQLTYuXDntsqyW2IxpNPiirFhfGQ1G5K1jN6Dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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