SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe700fe27623298e4d0ab9dae5d36be1a1cbc6e9ee87f8080850b216f9c018b' 
  AND token = '/bTJJRBcYzOPEQbmETkJCxLYsWBlpq5YjZKG6CGrzAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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